**2. Classification of insecticides**

#### **2.1 Organochlorine**

Organochlorines (chlorinated hydrocarbons) having organic compounds are attached to five or more chlorine atoms. It is the first group of pesticides that are synthesized and used in public health and agriculture. It is used against the management of a wide range of insects and having long-term residual effects in the atmosphere. The mode of action of these insecticides is disrupting the nervous system of the insects which caused paralysis and convulsions, which leads to death (**Figure 1**).

#### **2.2 Organophosphates**

The group "organophosphate" pesticides are considered to be one of the broadspectrum pesticides, which manage various numbers of pests because of their multiple functions. The organophosphate pesticides are biodegradable, cause very low environmental pollution, and are slow pest resistance [8].

#### **2.3 Carbamates**

The carbamates insecticides are similar to the organophosphates insecticides. Carbamates are derived from carbamic acid where organophosphates are the derivatives of phosphoric acid. Mode of action of carbamate pesticides and organophosphate pesticides are similar, that is, affecting the nervous system, that is, the transmission of nerve signals that caused the death [9].

#### **2.4 Synthetic pyrethroid**

A synthetic pyrethroid is a group of pesticides that are organic pesticide group that can be synthesized from natural pyrethrins.

*Review on the Impact of Insecticides Utilization in Crop Ecosystem: Their Prosperity and Threats DOI: http://dx.doi.org/10.5772/intechopen.100385*

### **Figure 1.**

*Classification of insecticides (Source: [7]).*
